Fundus-based and electroretinographic strategies for stratification of late-stage Vogt-Koyanagi-Harada disease patients

Abstract

Purpose: To propose an analytic framework for ocular fundus alterations in late-stage Vogt-Koyanagi-Harada (VKH) disease, to describe the characteristics of overall retinal function as measured with full-field electroretinography (ERG), and to correlate the intensity of the fundus changes with full-field ERG alterations and to stratify patients accordingly.

Design: Cross-sectional case series.

Methods: Forty-seven eyes of 26 patients with late-stage VKH disease (> 6 months past disease onset) followed-up at the University of São Paulo School of Medicine underwent fundus photography within 2 months of a full-field ERG examination, both according to predefined protocols. Fundus pictures were evaluated by two observers regarding diffuse fundus depigmentation, nummular lesions, pigment clumps, and subretinal fibrosis, and an overall analysis classified the fundus changes as mild, moderate, or severe. Full-field ERG results were analyzed according to fundus-based stratification and also were stratified into 3 groups solely on the basis of decreasing amplitudes (ERG based or cluster stratification). The concordance between fundus-based and full-field ERG-based stratification strategies was estimated.

Results: Overall fundus grading showed substantial interobserver concordance (kappa = 0.78). Comparison of full-field ERG parameters of the three fundus-based stratified groups showed diffusely diminished amplitudes with preservation of implicit times (P < .05). Fundus-based and full-field ERG-based stratification strategies also showed substantial concordance (kappa = 0.68).

Conclusions: The analytic framework for fundus findings proposed in this study seems reproducible and useful, because the severity categories do correlate with retinal function as measured by full-field ERG. This system may allow more precise exchange of information between practitioners as well as researchers with regard to identifying patients with greater retinal compromise rapidly as well as in comparison of outcomes of different treatment regimens.